1. Field of the Invention
The present invention relates to an x-ray image sensing device. More particularly, the present invention relates to an x-ray image sensing device suitable for the dual energy x-ray radiography.
2. Description of the Related Art
Radiographic techniques are widely used in modern medicine. In particular, a chest radiograph may provide much and important diagnosis information for chest bones and soft tissues. For example, the chest radiograph may be used for diagnosing bones or soft tissues of lungs, a chest bone structure, upper abdominal organs, a pulmonary vessel structure or cone space of the midthoracic.
Dual energy x-ray radiographic techniques are often used for the chest radiography. The dual energy x-ray radiographic technique is carried out by irradiating x-rays to a body twice in a row, and the two x-ray irradiations are a high energy x-ray and a low energy x-ray, respectively. Since the high energy x-ray and the low energy x-ray can lead to different image contrast, a clear image may be obtained by performing image processing to the sensing images obtained from the two different x-rays by using a calculator. For example, the processed image can only show a bone image or a soft tissue image.
The x-ray image sensing device is usually an indirect x-ray image sensing device, in which only one scintillator layer and one photodiode for sensing the x-ray is included. The x-ray through a human body is absorbed by the scintillator layer and a scintillator light is emitted. The emitted scintillator light is then absorbed by the photodiode and transformed to digital signals.
However, there are some problems which still cannot be resolved using the dual energy x-ray radiographic technique. During the two x-ray irradiations, processing error may occur if the x-ray source or the human body is moved, which is usually referred to as motion blur. In addition, even if the x-ray source and the human body are completely fixed during the two x-ray irradiations, the image may still be blurred due to the heart beating.
Therefore, an x-ray sensing device capable of resolving the motion blur problem and being suitable for the dual energy x-ray radiographic technique is needed.